adv7310 Analog Devices, Inc., adv7310 Datasheet - Page 49

• Manufacturer Part Number: adv7310
• Description: Multiformat 216 Mhz Video Encoder With Six Nsv 12-bit Dacs
• Manufacturer: Analog Devices, Inc.

HD SHARPNESS FILTER CONTROL AND
ADAPTIVE FILTER CONTROL
[Subaddress 20h, 38h–3Dh]
There are three filter modes available on the ADV7310/ADV7311:
sharpness filter mode and two adaptive filter modes.
HD Sharpness Filter Mode
To enhance or attenuate the Y signal in the frequency ranges
shown in the figures below, the following register settings must
be used: HD sharpness filter must be enabled and HD adaptive
filter enable must be set to disabled.
To select one of the 256 individual responses, the according
gain values for each filter, which range from –8 to +7, must
be programmed into the HD sharpness filter gain register at
Address 20h.
HD Adaptive Filter Mode
The HD adaptive filter threshold A, B, C registers, the HD
adaptive filter gain 1, 2, 3 registers, and the HD sharpness gain
register are used in adaptive filter mode. To activate the adaptive
filter control, the HD sharpness filter must be enabled and HD
adaptive filter enable must be enabled.
REV. A
SIGNAL:
INPUT
STEP
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
FILTER A RESPONSE (Gain Ka)
FREQUENCY (MHz)
SHARPNESS AND ADAPTIVE FILTER CONTROL BLOCK
Figure 43. Sharpness and Adaptive Filter Control Block
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
FILTER B RESPONSE (Gain Kb)
–49–
FREQUENCY (MHz)
The derivative of the incoming signal is compared to the three pro-
grammable threshold values: HD adaptive filter threshold A, B, C.
The recommended threshold range is from 16 to 235 although
any value in the range of 0 to 255 can be used.
The edges can then be attenuated with the settings in HD adap-
tive filter gain 1, 2, 3 registers and HD sharpness filter gain
register.
According to the settings of the HD adaptive filter mode control,
there are two adaptive filter modes available:
1. Mode A is used when adaptive filter mode is set to 0. In this
2. Mode B is used when adaptive filter mode is set to 1. In this
case, Filter B (LPF) will be used in the adaptive filter block.
Also, only the programmed values for Gain B in the HD sharp-
ness filter gain, HD adaptive filter gain 1, 2, 3 are applied when
needed. The Gain A values are fixed and cannot be changed.
mode, a cascade of Filter A and Filter B is used. Both set-
tings for Gain A and Gain B in the HD sharpness filter gain,
HD adaptive filter gain 1, 2, 3 become active when needed.
1.6
1.5
1.4
1.3
1.2
1.1
1.0
0
FREQUENCY RESPONSE IN SHARPNESS
FILTER MODE WITH Ka = 3 AND Kb = 7
ADV7310/ADV7311
2
FREQUENCY (MHz)
4
6
8
10
12